Readout device for numeral display unit

ABSTRACT

A readout device for a numeral display unit, such as a digital clock, of the type having a rotary numeral wheel with a plurality of numerals indicated thereon at successive positions angularly displaced with respect to the axis thereof is provided. The readout device is further provided with a plurality of switching means disposed about the wheel in a pattern encoded according to a given truth table. Switch means activated by said switching means are also provided for detecting the pattern and producing an electrical signal in response to the detection.

United States Patent 1 Shigeta READOUT DEVICE FOR NUMERAL DISPLAY UNIT [75] lnventor: Shizuo Shigeta, Funabashi, Japan [73] Assignee: Toyo Radio Co., Ltd., Tokyo, Japan [22] Filed: Jan. 31, 1972 [21] Appl. No.: 222,181

[30] Foreign Application Priority Data Sept. 29, 1971 Japan 46/89525 [52] U.S. Cl. 58/125, 235/1 C [51] Int. Cl

[58] Field of Search 235/61 PD, 92 EA, 235/92 T, 92 A, 92 BN, 92 ED, 1 C; 58/125 C, 6 R, 125 R, 126 R, 126E; 340/347 P,

[56] References Cited UNITED STATES PATENTS 2,127,733 8/1938' Herbst 235/61 PD X 2,302,769 11/1942 Haselton et al 235/61 PD X 2,344,254 3/1944 Leathers et al..... 235/61 PD X 2,855,585 10/1958 Quinby 235/92 EA X 2,896,845 7/1959 Hansen et al 235/92 EA X 2,966,670 12/1960 Foss 340/347 P 3,449,736 6/1969 Little 3401204- 3,456,123 7/1969 Pihl 340/309.4 3,484,780 12/1969 Kamoi et a1. 340/204 X 3,497,138 2/1970 Fisher 235/61 PD FOREIGN PATENTS OR APPLICATIONS 674,698 12/1964 Italy 235/61 PD 339,745 8/1959 Switzerland 235/61 PD Primary Examiner-Richard B. Wilkinson Assistant Examiner-Pat Salce Att0rneyDavid S. Kane et al.

[57] ABSTRACT A readout device for a numeral display unit, such as a digital clock, of the type having a rotary numeral wheel with a plurality of numerals indicated thereon at successive positions angularly displaced with respect to the axis thereof is provided. The readout device is further provided with a plurality of switching means disposed about the wheel in a pattern encoded according to a given truth table. Switch means activated by said switching means are also provided for detecting the pattern and producing an electrical signal in response to the detection.

3 Claims, 6 Drawing Figures PAIENIEDMI 23 ms SHEET 2 BF 3 &5,

READOUT MEANS FIG. 3A

PAIENIEBucraama 3.766331 SHEET 3 0f 3 READOUT DEVICE FOR NUMERAL DISPLAY UNIT BACKGROUND OF THE INVENTION The present invention relates to a device for reading and producing a signal representative of a numerical indication on a rotary numeral display device. The numerical display device may, for example, comprise a digital clock, digital meter, or the like.

In the processing of data on an electronic computer, it is sometimes necessary to know the time and date on which the processing occurs. In the past, this need has been met by a binary signal, representing the current time, supplied from a counter operated by dividing the output of an oscillator which drives an electrical clock. Such prior art devices require a frequency dividing counter which must be arranged so that the count in the counter coincides with the desired time. This arrangement is expensive and involves relatively complicated and troublesome arrangement and adjustment.

In view of the above, it is the principal object of the present invention to provide a relatively simple device for reading the numeral currently indicated on a numerical display unit and producing an electrical output in the form of a digital signal representative of the indicated numeral. As stated, the indicated numeral may, for example, comprise the time of day, the number of kilowatt hours consumed, the quantity of water or gasoline consumed or the like.

SUMMARY OF THE INVENTION The above and other beneficial objects and advantages are attained in accordance with the present invention by providing a numerical display device of the type comprising at least one rotary wheel having a plurality of numerals disposed in successive angular positions about the wheel periphery and adapted to provide selective indication of a numeral, the indication being determined by the rotational position of the wheel periphery with regard to a fixed reference. The display device further includes a plurality of switching means equal in number'to the numerals affixed to the wheel and adapted to rotate with the'wheel. The switching means are affixed to the wheel in a pattern encoded according to a given truth table. A multiplicity of. switch means is fixed relative to the rotational axis of the wheel and positioned so that at least some of the switch means are successively operatively coupled to at least some of the switching means and thereby able to detect the pattern at any given moment. Readout means connected to the switch means are also provided adapted to generate'an electrical signal in response to the detection.

BRIEF DESCRIPTION OF DRAWINGS In the accompanying drawings:

FIG. 1 is a top plan view, partly in section, of a numerical display unit in-the form of a digital clock constructed'in accordance with the present invention;

FIG. 2 is a front elevational view of the clock of FIG.

FIG. 3 is a fragmentary plan view, in section, of the digital clock;

. FIG. 3a is a simplified diagrammatic drawing of the connection between the numeral display and a readout device;

FIG. 4 is a side elevational sectional view taken along reference line a-a of FIG. 3; and

FIG. 5 is a side elevational view.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention is illustrated in the accompanying drawings wherein similar parts bear the same reference numeral throughout the several views. In the accompanying description, the present invention is exemplified by a digital clock provided with a readout device. As previously stated, it should be understood that the present readout device is applicable to any numerical display unit having a rotary numeral wheel.

The digital clock of the present invention is generally rectangular in shape having a front panel 1, left side plate 2, right side plate 3 and a rear plate 4.

Shaft 5 extends through plates 2 and 3 and is suitably journaled for rotation. A plurality of numeral wheels is rotatably mounted about shaft 5. Accordingly, wheel 6 is provided for hour representation, wheel 7 is provided for 10s unit of minutes representation and wheel 8 is provided for unit of minutes representation. In addition, as is customary with such digital clocks, an operation indicating wheel 9 is also provided. The operation indicating wheel 9 is provided with a knurled periphery and moves at a relatively rapid rate so that the operation of the clock may readily be detected. Wheels 6, 7, 8 and 9 are disposed in sequence from left to right along the length of shaft 5.

Each of the numeral wheels 6, 7 and 8 is cylindrical in shape and carries numerical indication about its outer periphery. Accordingly,-wheel 6 bears the numerals 1 through 12 at equiangular intervals; the outer periphery of wheel 7 bears the numerals 0 through 5 at equiangular intervals and the outer periphery of wheel 8 bears the numerals 0 through 9 at equiangular intervals. The wheels 6, 7 and 8 are of the same diameter.

A gear shaft 10 extends between the left and right plates 3 and 4 at a position adjacent to the outer periphery of the wheels. Gears ll, 12 and 13 arerotatably mounted on shaft 10 and the adjacent numeral wheel and indication wheel 9 are rotationally coupled together at a given ratio of revolution through gears 11, 12 and 13. A motor 14 is secured to the back of plate 4. Motor 14 has a shaft which meshes through intermediate gears 15, 16 and 17 with drive wheel 18. Drive wheel 18 if formed integrally on one side of the operation indicating wheel 9 as shown in FIG.- 1,

As motor 14 rotates, numeral wheel 8 completes one revolution in 10 minutes, numeral wheel 7 completes one revolution in 60 minutes, and numeral wheel 6 completes one revolution in 12 hours. The rotation of these wheels occurs stepwise to form an angular interval'between the numerical impressions ln this connection, panel I is provided with windows 19;, 20 and 21 positioned so as to enable viewing ofv the wheels. The

preceding description is well known in the art of digital v ent invention, the switching means comprise small pieces of magnetic material secured in the space between adjacent numerals on each of the numeral wheels. The encoded pattern is a binary representation of the numerals on the wheel. Referring to wheel 6, it may be noted that four axial column positions, 23, 24, 25 and 26 are provided between each pair of adjacent numbers. The presence or absence of magnetic material in a particular column serves to establish the binary code with position 23 corresponding to the least significant digit, position 24 corresponding to the second digit, position 25 corresponding to the third digit and position 26 corresponding to the most significant digit. Thus, the presence of magnetic material 27 corresponds to a binary one and the absence of such material corresponds to a binary zero. Thus, the binary coded numeral appearing below numeral 2 in FIG. 1 is 1-0 -1-0 corresponding to the hour 10, the numeral appearing in window 19. The binary coded numeral is displaced along wheel 6 so that the proper binary coded number appears at the top of the wheel when the numeral is visible through window 19. In a similar manner, wheel 7 has binary coded information 29 and wheel 8 has binary coded information30. Thus, binary numeral -1-1 appears at the top of wheel 7 when the numeral 3 appears in window and binary number 0-1-0-1 appears at the top of wheel 8 when numeralS appears in window 21. As stated, the binary coded material serves as switching means for switch means used to detect and readout the binary code in the form of electrical signals.

The detection means is illustrated in FIGS. 3-5. Referringto FIG. 3,-.it is notedthat a pair of transverse bars 31 and 32 extend across the top of plates 3 and 4 adjacent the front and rear sides thereof. A-printed circuit board 33. is mounted on the-bars. A plurality of magneticv detecting elements in the form of reed switches is mounted on the interior surface of board 33. The switches are provided in'indexed registry with the axial positions of the magnetic material associated with wheels 6, 7and 8. Accordingly, four reed switches, 34, 35, 36 and. 317 are mounted on the board to align respectively with axial positions 26, 25, 24 and 23. Similarly, switches 38, 39 and 40 are aligned with the axial positions associated with wheel 7 and switches 41, 42, Band 44 are aligned with the axial positions associated with. wheel 8 Thus, the encoded pattern of the magnetic material located opposite the switches will activate the switchesin a pattern representative of the numerals appearing through windows 19, 20 and 21.

As shown, one end of each of the reed switches is connected-to a common wire 45 which, in turn, is connected to a terminal 71 at one end of board 33. The other end of each of the reed switches is connected to a separate terminal. V l Because thenumeral wheels 7 and 8 are physically located close to each other and thus, would require'the close location of switches 40 and, which may cause a malfunction, the group of reed switches 38, 39 and 40 and the group of reed switches 41, 42, 43 and 44 are staggered fore and aft, as shown.

As stated, it is common in digital clocks of the type described for the numeral wheels 6, 7 and 8 to rotate stepwise. During the periods of rotation, the operation of the various reed switches may not properly reflect thetime displayed and, hence, it is desirable to inhibit thereading operation during such period. To this end,

pieces of permanent magnet (see FIG. 1) are provided on the numeral wheel extending between adjacent patterns. A detecting reed switch 51 is mounted on board 33 in registry with magnet 21 so that the reed will be activated by magnet 50 when the wheel rotates. Reed 51 is connected to a terminal of board 33 in such a manner as to inhibit the reading operation when the reed switch is closed even if a demand for a reading operation is issued by computer as shown in FIG. 3a wherein the single line 73 represents the several connections between the various terminals of board 33 and readout device 75. It should be noted that while the drawings show inhibit means only in conjunction with wheel 8, similar means may be provided forthe other wheels. In order to allow for constant readout, even during periods of inhibit, a buffer may be added to store the arrangement of the last settings of reed switches during the inhibit period.

As was previously stated, wheel 6 contains the numerals 1 through 12 and thus, no automatic distinction is made between AM and PM readings. To effect such distinction in the readout afforded by the present invention, shaft 57 is rotatably mounted through plate 2 as shown in FIG. 5. A rotating plate 52 is mounted on shaft 57 externally of plate 2. Permanent magnets 53 and 54 are movably secured to the opposite ends of plate 52-and a pair of stationary magnets 55 and 56 are secured to the left-hand side of plate 2 along the circular path of motion of movable magnets 53 and 54. The stationary magnets are positioned 90 apart. Shaft 57 extends into wheel 6' and a cam disc 58 is mounted on its extreme .end. Wheel 6 carries a projection 59 on its inner periphery at a position aligned with cam disc 58. Reed switch 60 ismounted on board 33 in aligned relationship with the rotating plate. When the numeral wheel 6 assumes the position in which 12 oclock is displayed, projection 59 rotationally drives the cam 58 whereby the movable magnet 54 is urged away from the stationary magnet 55 and moves toward magnet 56 while the magnet 53 is moved away from reed switch 60. After a complete revolution of wheel 6, cam plate 58 is againdriven by the projection, and magnet 53 is attracted. by magnet 55 while magnet 54 comes opposite reed switch 60. In this manner, everytime numeral wheel 6 displays 12 oclock, one of the movable magnets is moved toward' or away from the reed switch.;

Thus, in-accordance with the above, the time of day displayed by wheels 6, 7 and 8 in windows 19,20 and 21 is converted into digital signalsin the formof actuated and nonactuated reed switches. By connecting the reed switches with a load, the time of day can be read-- out in the form of digital signals. It should be apparent that the magnetic elements and reed switches may be replaced by other similar .switching and switch elements suchas Hall elements, magnetosensitive diodes or othermagnetic detecting elements. Alte rnately, the

may be encoded according to any other suitable truth table.

Having thus described the invention, what is claimed is:

1. In a numerical display device of the type comprising at least one rotary wheel adapted to rotate during discrete time periods having a plurality of numerals disposed in successive angular positions about the wheel periphery and adapted to provide selective indication of a numeral, said indication being determined by the rotational position of the wheel periphery with regard to a fixed reference, the improvement comprising: a plurality of switching means equal in number to said numerals affixed about said wheel periphery in a pattern encoded to said numerals according to a given truth table, said switching means being adapted to rotate with said wheel and disposed in identical successive angular positions about the wheel periphery; a multiplicity of switch means fixed relative to the rotational axis of said wheel and positioned so that at least some of said switch means are successively operatively coupled to at least some of said switching means for detecting said pattern; readout means connected to said switch means, said readout means providing indication of the particular switch means operated by said switching means at any particular time; and, means to inhibit said readout means during said periods of rotation.

2. The display device in accordance with claim 1 wherein said switching means comprise magnetic members and said switch means include magnetic detecting elements fixed along the path of rotation of said wheels adjacent said switching means.

3. The display device in accordance with claim 2 wherein said inhibiting means comprises a magnetic member extending between each of said successive angular positions, a reed switch fixed adjacent the path of rotation of said wheel and magnetic coupling with said inhibiting magnetic member, and circuit means extending between said last referenced reed switch and said readout means. 

1. In a numerical display device of the type comprising at least one rotary wheel adapted to rotate during discrete time periods having a plurality of numerals disposed in successive angular positions about the wheel periphery and adapted to provide selective indication of a numeral, said indication being determined by the rotational position of the wheel periphery with regard to a fixed reference, the improvement comprising: a plurality of switching means equal in number to said numerals affixed about said wheel periphery in a pattern encoded to said numerals according to a given truth table, said switching means being adapted to rotate with said wheel and disposed in identical successive angular positions about the wheel peRiphery; a multiplicity of switch means fixed relative to the rotational axis of said wheel and positioned so that at least some of said switch means are successively operatively coupled to at least some of said switching means for detecting said pattern; readout means connected to said switch means, said readout means providing indication of the particular switch means operated by said switching means at any particular time; and, means to inhibit said readout means during said periods of rotation.
 2. The display device in accordance with claim 1 wherein said switching means comprise magnetic members and said switch means include magnetic detecting elements fixed along the path of rotation of said wheels adjacent said switching means.
 3. The display device in accordance with claim 2 wherein said inhibiting means comprises a magnetic member extending between each of said successive angular positions, a reed switch fixed adjacent the path of rotation of said wheel and magnetic coupling with said inhibiting magnetic member, and circuit means extending between said last referenced reed switch and said readout means. 